CN205489460U - CT open circuit protection device - Google Patents
CT open circuit protection device Download PDFInfo
- Publication number
- CN205489460U CN205489460U CN201620156416.7U CN201620156416U CN205489460U CN 205489460 U CN205489460 U CN 205489460U CN 201620156416 U CN201620156416 U CN 201620156416U CN 205489460 U CN205489460 U CN 205489460U
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- China
- Prior art keywords
- circuit
- diode
- open
- pressure cell
- protecting device
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn - After Issue
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Abstract
The utility model discloses a CT open circuit protection device, the device is two field effect triodes as follows mainly, a rectifying filter circuit, it constitutes to detect drive circuit and protection circuit, the source electrode of two field effect triodes all is connected to rectifier circuit's direct current output negative pole, the drain electrode of two field effect triodes is connected to two inputs of protection device respectively, the grid of two field effect triodes all is connected to drive circuit's output, two inputs of rectifier circuit's AC input connect protection device, two diode positive poles of protection circuit connect the source electrode of two field effect triodes respectively, the pressure -sensitive element that establishes ties after the negative pole is connected connects the grid of two field effect triodes, the utility model discloses the reliable operation, it is small, self low power dissipation.
Description
Technical field
This utility model relates to a kind of protection device, particularly relates to the CT open-circuit protecting device of a kind of power system.
Background technology
nullThe CT of power system，Namely current transformer，Its secondary side is in operation open circuit，The voltage being likely to cause on secondary coil is increased to several kilovolts，Volts the most up to ten thousand，This by serious threat to the person safety and equipment safety，Therefore，Harm in order to prevent CT second open circuit from causing occurs，Occur in that various CT open-circuit protecting device，But there is respective drawback，Chinese patent publication CN204858552U discloses a kind of Installation of Open-circuit Protection for Current Transformers，The fet of two differential concatenations that secondary side at current transformer is in parallel and drive circuit thereof，Rectification circuit when this protection device、Filter circuit、Testing circuit and drive circuit detect when high voltage occurs in CT open running，Drive the fet conducting of two differential concatenations，Inhibit the dangerous high voltage being likely to occur，This protection device volume is little，Cost is relatively low，But，This device is not turned at detection two fets of time period，Now by being connected in parallel on the two-way Transient Suppression Diode of CT secondary side to limit CT secondary voltage，Two fets of protection and other elements simultaneously，Restriction due to two-way Transient Suppression Diode self performance，When CT secondary current is bigger，Two-way Transient Suppression Diode self and the damage of fet easily occur.
Summary of the invention
The purpose of this utility model is to provide a kind of CT open-circuit protecting device; when this device is not only able to open circuit in the range of CT is operated in rated current; CT secondary side can be effectively suppressed to produce dangerous high voltage, and in the case of CT electric current is relatively big during second open circuit, also can reliably working.
nullIn order to achieve the above object，The technical solution adopted in the utility model is: device mainly has two fets、Rectification circuit、Filter circuit and detection drive circuit composition，The source electrode of two fets is all connected to the direct current output negative pole of rectification circuit，The drain electrode of two fets is connected respectively to two inputs of protection device，The grid of two fets is all connected to the outfan of drive circuit，Two ac input ends of rectification circuit are connected respectively to two inputs of device，Filter circuit connects DC output end positive pole and the negative pole of rectification circuit，It is further connected with two diodes between two inputs of protection device，And pressure cell，The positive pole of two diodes connects two inputs of protection device respectively，The negative pole of two diodes connects together，And be connected with the negative pole of pressure cell，The positive pole of pressure cell connects the grid of two fets，When this device is operated in the detection period，Although if now the secondary voltage of transformer has reached the setting voltage of testing circuit，But detection drive circuit is not the most able to do in time, output drives the driving voltage of two fet conductings，At this moment pressure cell punctures，The secondary voltage of transformer is delivered to the grid of two fets，When grid voltage exceedes its threshold voltage，Two fets begin to turn on，Thereby inhibiting bis-high voltages of CT.
Described pressure cell can use Zener diode.
Described pressure cell can also use Transient Suppression Diode.
Described Transient Suppression Diode can be unidirectional Transient Suppression Diode.
Described Transient Suppression Diode can also be two-way Transient Suppression Diode, and when using two-way Transient Suppression Diode, its closure is regardless of both positive and negative polarity.
Described pressure cell can also use varistor, and its closure is regardless of both positive and negative polarity.
Described two the diode preferred package being connected between two inputs common cathode composition element together.
In order to reduce the voltage that filter circuit bears, can connect between the DC output end of described rectification circuit and described filter circuit a buck diode, the negative pole of buck diode connects the DC output end positive pole of rectification circuit, and the positive pole of buck diode connects the positive pole of filter circuit.
Described buck diode can be Zener diode
Described buck diode can also be unidirectional Transient Suppression Diode.
Described buck diode can also is that two-way Transient Suppression Diode, and when using two-way Transient Suppression Diode, closure is regardless of both positive and negative polarity.
The beneficial effects of the utility model are: 1. work is more reliable, owing to this device restrains high voltage in the detection time period also with two fets, and the two field effect transistor is the powerful field effect transistor selected, it is to avoid two-way transient state suppresses the problem that two poles are burnt because of overpower；2. low cost, instead of expensive two-way transient state with cheap general-purpose diode and suppresses two poles, make device holistic cost reduce；3. volume reduces further, and owing to general-purpose diode suppresses the volume of two poles much smaller than two-way transient state, therefore the volume of device also can reduce accordingly.
Accompanying drawing explanation
Fig. 1 is the electrical schematic diagram of first embodiment of this utility model；
Fig. 2 is the electrical schematic diagram of another embodiment of this utility model.
In figure: Q1. fet, Q2. fet, Q3. audion, U1. adjustable precise shunt regulator, D1. diode, D2. diode, D3. rectification circuit, D4. buck diode, YM. pressure cell, C1. filter circuit, R1. resistance, R2. resistance, R3. resistance, R4. resistance, R5. resistance, R6. resistance.
Detailed description of the invention
Being described in further detail detailed description of the invention of the present utility model with embodiment below in conjunction with the accompanying drawings, following example are used for illustrating this utility model, but are not limited to scope of the present utility model.
nullIn first shown in Fig. 1 embodiment，CT open-circuit protecting device mainly has two fet Q1、Q2、Rectification circuit D3、Filter circuit C1、And detection drive circuit composition，Two fet Q1、The source electrode of Q2 is all connected to the direct current output negative pole GND of rectification circuit D3，Two fet Q1、The drain electrode of Q2 is connected respectively to two input A of protection device、B，Two fet Q1、The grid of Q2 is all connected to the outfan D of drive circuit，Two ac input ends of rectification circuit D3 are connected respectively to two input A of device、B，Filtering wave circuit C1 meets the DC output end positive pole VCC and negative pole GND of rectification circuit D3，Two input A of protection device、Two diode D1 it are further connected with between B、D2 and pressure cell YM，Two diode D1、The positive pole of D2 meets two input A of protection device respectively、B，Two diode D1、The negative pole of D2 connects together，And be connected with the negative pole of pressure cell YM，The positive pole of pressure cell YM meets two fet Q1、The grid of Q2.
Detection drive circuit is made up of Q3, U1, R1, R2, R3, R4, R5 and R6, when voltage between DC output end positive pole VCC and the negative pole GND of rectification circuit D3 reaches certain value, Q3 turns on, D point output HIGH voltage, drives two fet Q1, Q2 conductings.
Described pressure cell YM can use Zener diode, unidirectional Transient Suppression Diode, two-way Transient Suppression Diode or varistor, and when using two-way Transient Suppression Diode or varistor, its closure is regardless of both positive and negative polarity.
Two diode D1, D2 preferred package common cathode diode combination together.
Another embodiment shown in Fig. 2, it is on the basis of first embodiment, connect between the DC output end and described filter circuit C1 of described rectification circuit D3 buck diode D4, the negative pole of buck diode D4 connects the DC output end positive pole of rectification circuit D3, the positive pole of buck diode D4 connects the positive pole of filter circuit C1, buck diode D4 can use Zener diode, unidirectional Transient Suppression Diode or two-way Transient Suppression Diode, and when using two-way Transient Suppression Diode, its closure is regardless of both positive and negative polarity.
Detection drive circuit can also use other circuit of prior art, exports high level when CT secondary voltage reaches setting value, transfers low level to when the voltage of filter circuit is reduced to and is unsuitable for and drives field effect transistor conducting.
Claims (10)
- null1. a CT open-circuit protecting device，Mainly there are two fet (Q1、Q2)、Rectification circuit (D3)、Filter circuit (C1)、And detection drive circuit composition，Two fet (Q1、Q2) source electrode is all connected to the direct current output negative pole (GND) of rectification circuit (D3)，Two fet (Q1、Q2) drain electrode is connected respectively to two input (A of protection device、B)，Two fet (Q1、Q2) grid is all connected to the outfan (D) of drive circuit，Two ac input ends of rectification circuit (D3) are connected respectively to two input (A of device、B)，Filter circuit (C1) connects DC output end positive pole (VCC) and the negative pole (GND) of rectification circuit (D3)，It is characterized in that: two input (A of protection device、B) two diode (D1 it are further connected with between、And pressure cell (YM) D2)，Two diode (D1、D2) positive pole meets two input (A of protection device respectively、B)，Two diode (D1、D2) negative pole connects together，And be connected with the negative pole of pressure cell (YM)，The positive pole of pressure cell (YM) meets two fet (Q1、Q2) grid.
- CT open-circuit protecting device the most according to claim 1, it is characterised in that: described pressure cell (YM) is Zener diode.
- CT open-circuit protecting device the most according to claim 1, it is characterised in that: described pressure cell (YM) is Transient Suppression Diode.
- CT open-circuit protecting device the most according to claim 3, it is characterised in that: described pressure cell (YM) is unidirectional Transient Suppression Diode.
- CT open-circuit protecting device the most according to claim 3, it is characterised in that: described pressure cell (YM) is two-way Transient Suppression Diode, and its closure is regardless of both positive and negative polarity.
- CT open-circuit protecting device the most according to claim 1, it is characterised in that: described pressure cell (YM) is varistor, and its closure is regardless of both positive and negative polarity.
- 7. according to the CT open-circuit protecting device described in claim 1,2,4,5 or 6; it is characterized in that: between DC output end and the described filter circuit (C1) of described rectification circuit (D3), be also in series with buck diode (D4); the negative pole of buck diode (D4) connects the DC output end positive pole of rectification circuit (D3), and the positive pole of buck diode (D4) connects the positive pole of filter circuit (C1).
- CT open-circuit protecting device the most according to claim 7, it is characterised in that: described buck diode (D4) is Zener diode.
- CT open-circuit protecting device the most according to claim 7, it is characterised in that: described buck diode (D4) is unidirectional Transient Suppression Diode.
- CT open-circuit protecting device the most according to claim 7, it is characterised in that: described buck diode (D4) is two-way Transient Suppression Diode, and its closure is regardless of both positive and negative polarity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620156416.7U CN205489460U (en) | 2016-03-02 | 2016-03-02 | CT open circuit protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620156416.7U CN205489460U (en) | 2016-03-02 | 2016-03-02 | CT open circuit protection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205489460U true CN205489460U (en) | 2016-08-17 |
Family
ID=56658976
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620156416.7U Withdrawn - After Issue CN205489460U (en) | 2016-03-02 | 2016-03-02 | CT open circuit protection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205489460U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105790215A (en) * | 2016-03-02 | 2016-07-20 | 闫堂锁 | CT open-circuit protection device |
-
2016
- 2016-03-02 CN CN201620156416.7U patent/CN205489460U/en not_active Withdrawn - After Issue
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105790215A (en) * | 2016-03-02 | 2016-07-20 | 闫堂锁 | CT open-circuit protection device |
| CN105790215B (en) * | 2016-03-02 | 2018-03-09 | 闫堂锁 | CT open-circuit protecting devices |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20160817 Effective date of abandoning: 20180309 |